Fixed angle, one piece golf clubs are the norm for golfers today, especially those players who compete in tournaments, which require strict adherence to the United States Golf Association (USGA) rules of play. The USGA provides governance for the game worldwide, jointly administering the Rules of Golf and establishing equipment standards. More specifically, the equipment standards, as they apply to golf clubs and putters in particular, are precise and rigid as to the size, shape, angle, material and method of use (stroke or swing). Thus, fixed parameter clubs have become the standard in nearly every tournament golfer's bag.
A golf club is defined as an implement designed to be used for striking the ball and generally comes in three forms: woods, irons and putters distinguished by shape and intended use. A putter is a club with a loft not exceeding ten degrees designed primarily for use on the putting green. Putters are permitted to have negative loft. However, a loft of less than −15 degrees would not be considered “traditional and customary in form and make” by the USGA. Additionally, the club must not be substantially different from the traditional and customary form and make, and must be composed of a shaft and a head. All parts must be fixed so that the club is one unit, and it must have no external attachments that affect the performance of the club.
This is interpreted to mean that no part of the golf club should be designed to move, nor should it be promoted as doing so. Therefore, if any part of a club were to incorporate moving powder, pellets, liquid, vibrating wires, rollers, tuning forks, or any number of other features which could be considered a “moving part,” it would be in breach of this Rule. Additionally, this provision is interpreted to mean that with some exceptions, when assembled, all parts are bonded such that they require heating to loosen. Of course, this does not apply to clubs with permitted adjustable features.
The following requirements typically apply to all permissible methods of adjustment in a club: (i) the adjustment cannot be readily made; (ii) all adjustable parts are firmly fixed and there is no reasonable likelihood of them working loose during a round; and, (iii) all configurations of adjustment conform to the USGA Rules. During a stipulated round, the playing characteristics of a club must not be purposely changed by adjustment or by any other means.
In order to preserve the integrity of this Rule, it clearly states that it must not be too easy for a player to make adjustments during the course of a stipulated round. This is interpreted to mean that adjustments must require the use of a special tool, such as an Allen key, a Phillips screwdriver or a custom-made tool or device. It must not be possible to make the adjustment just by using the fingers, or some other object which would normally be kept in a golfer's pocket, such as a coin or a pitch-mark repair tool. The above restrictions have been included in the Rules in order to encourage the player to make all of the necessary adjustments to his clubs before starting his round, and to protect him from either unwittingly or purposely making adjustments during a round.